The present invention relates to a pipe handling apparatus adapted to automatic drilling operations, in which drill pipes are manipulated between substantially horizontal initial or final positions, and approximately vertical drill centre positions, for use with a top mounted drilling device which is rotatable about a substantially horizontal first axis.
Automatic systems for drilling operations are previously known which furthermore are able to carry out tripping operations, e.g. when a drill bit is to be replaced or logging or service operations are to be carried out. It is known that to pull out a drill string from oil or gas wells in the conventional way are very time consuming operations. Tripping operations are especially time consuming in case of drilling at greater depths requiring more frequent replacements of drill bits. The total drilling time in case of deep wells is, thus, considerably increased and results in increased costs.
U.S. Pat. No. 3,404,741 discloses an automated system for drilling and pipe manipulation. Drill pipes are placed in a horizontal position halfway up in the derrick before the pipes are manipulated into a vertical position. The structure comprises a drilling device which is rotatable about a horizontal axis. In its horizontal or lying position the pipe may be inserted into the drilling device which is subsequently raised permitting the pipe to be moved into a vertical position. At its other end the pipe is guided by a carriage moving on rails. During the raising operation the pipes are only supported at their end portions and, obviously, only short pipe lengths can be raised in this way. In order to reduce the time consumption it is, however, common and desirable today to manipulate pipe sections or stands comprising two or three assembled single pipes, i.e. sections that may be up to 30 m long.
U.S. Pat. No. 3,986,619 also describes equipment for manipulating pipes in order to move drill pipes from a horizontal into a vertical position. Entire pipe stands are manipulated by this system. The equipment comprises a mechanism elevating the stands in a horizontal position from the drill floor up to a predetermined level. The equipment for manipulating pipes comprises a series of blocks, pulleys and wires and is, apparently not adapted for automated operation.